.st1{
    background-image: linear-gradient(to right, #434343 0%, black 100%)
}
.st2{
    width: 50%; height: 500px; float: left
}
.st3{
    height: 100%; margin: auto
}
.st4{
    width: 50%; height: 500px; float: right
}
.st5{
    height: 100%; margin: auto
}